FLOW CONTROL VALVE FOR CONSTRUCTION EQUIPMENT

Description

TECHNICAL FIELD

[0001] The present invention relates to a construction equipment and more particularly, a flow control valve of a construction equipment for controlling a flow rate supplied from a hydraulic pump to a hydraulic actuator.

BACKGROUND OF THE INVENTION

[0002] A flow control valve of a construction equipment as shown in Fig. 1 according to the conventional technology has a valve body (2) installed on the path between a hydraulic pump (not shown) and a hydraulic actuator (1). A switchable spool (3) is provided within the valve body (2) so that by switching, a hydraulic oil of the hydraulic pump can be supplied to the hydraulic actuator (1) and a hydraulic oil discharged from the hydraulic actuator (1) can return to a hydraulic oil tank (not shown).

[0003] Within the valve body (2) are provided a pump path (4) supplying the hydraulic oil from the hydraulic pump, a supply path (5) communicating with the pump path (4) and the actuator ports (6, 7) connected to the hydraulic actuator (1).

[0004] In the flow control valve as describe above, the spool (3) is shifted to the left side in the figure when the pilot signal pressure is applied in the right side of the spool (3). At this time, a check valve (11) is moved upwards in the figure and opened by the hydraulic oil supplied to the pump path (4) from the hydraulic pump.

[0005] Accordingly, the hydraulic oil supplied to the pump path (4) is delivered to the hydraulic actuator (1) by way of the supply path (5), a spool notch (8), and the actuator port (6) in order. At the same time, the hydraulic oil discharged from the hydraulic actuator (1) returns to the hydraulic oil tank by way of the actuator port (7), a spool notch (9), and a tank path (10) in order. Thus, the hydraulic actuator (1) is actuated in contraction.

[0006] If the hydraulic actuator (1) is the boom cylinder that makes the boom up and down, the boom cylinder is actuated in contraction due to the weight of the boom itself before the bucket digs into the ground, even though the hydraulic oil is not supplied to the small chamber of the cylinder. Therefore, the contraction of the boom cylinder makes the hydraulic oil supplied to the small chamber unnecessary, which otherwise causes the problem of lowering the fuel efficiency due to the waste of the hydraulic energy.

[0007] GB 2 313 412 A describes a return fluid regeneration device for construction vehicles. In the regeneration device, an orifice is provided on a return-side internal line of a directional control valve of an actuator. A regeneration line is arranged between the return-side internal line and a return line extending to a return tank and is selectively connected to the return-side internal line during a weight operation of the actuator. A regeneration branch line is branched from the return-side internal line downstream of orifice and is connected to a supply-side internal line of the valve, thus selectively feeding the return fluid from the return-side internal line to the supply-side internal line and thereby regenerating the return fluid. First and second check valves are provided on the regeneration line and branch line, respectively. The regeneration device regulates the moving speed of the actuator while simultaneously preventing the generation of high pressure in a fluid supply line.

SUMMARY OF THE INVENTION

[0008] It is an object of the present invention to provide a flow control valve for a construction equipment that can improve the fuel efficiency by reducing the hydraulic oil from the hydraulic actuator when the pressure of the hydraulic oil returning to the hydraulic oil tank from the hydraulic actuator is higher than the predetermined pressure.

[0009] This object is achieved by a flow control valve of claim 1.

[0010] To achieve the above and other objects, in accordance with an embodiment of the present invention, there is provided a flow control valve for a construction equipment comprising; a valve body installed on the path between a hydraulic pump and a hydraulic actuator and configured with a supply path communicating with a pump path supplying the hydraulic oil from the hydraulic pump and the actuator ports (6, 7) connected to the hydraulic actuator;
a switchable spool provided within the valve body so that by switching, the hydraulic oil of the hydraulic pump is supplied to the hydraulic actuator, and a hydraulic oil discharged from the hydraulic actuator is returned to a hydraulic oil tank;
a pressure chamber provided within the spool, which communicates with the supply path and an actuator port on one side;
a signal pressure path provided within the spool, which communicates with the actuator port on the other side and the pressure chamber; and
a flow control valve provided within the pressure chamber, which is switched by the returning oil supplied through the signal pressure path and blocks the opening part when the pressure of the hydraulic oil returning to the hydraulic oil tank from the hydraulic actuator exceeds the predetermined pressure. The flow control valve is configured with a valve spring to support elastically the maximum open state of the opening part of the flow control valve as the initial state. The flow control valve is configured with a drain path formed in a spool so as to communicate with a back pressure chamber and a tank path and to remove the remaining pressure of the back pressure chamber by the valve spring.

[0011] The flow control valve may be configured with a first path formed in the spool so as to communicate with the supply path, a second path communicating with the actuator port on one side, of which the opening area is controlled when the flow control valve is switched by the hydraulic oil supplied to the hydraulic actuator from the hydraulic pump as the spool is switched, and a third path communicating with a first path and a second path of the flow control valve.

[0012] The flow control valve may also be configured with a plug installed on an arbitrary position along a third path so as to prevent the hydraulic oil from flowing reversely to the actuator port on the other side as the hydraulic oil is supplied to the actuator port on one side.

ADVANTAGEOUS EFFECT

[0013] According to the embodiment of the present invention having the above-described configuration, a flow control valve for a construction equipment can bring the effect of improving the fuel efficiency by avoiding the unnecessary consumption of the hydraulic oil as the spool is switched by the returning oil from the hydraulic actuator and thereby blocking the hydraulic oil supplied from the hydraulic actuator when the pressure of the hydraulic oil returning to the hydraulic oil tank from the hydraulic actuator is higher than the predetermined pressure. In addition, since the flow control valve is provided within the spool, the configuration allows the main control valve (MCV) to be arranged easily and increases the design flexibility.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] 

Fig. 1 is the end view of the flow control valve for the construction equipment according to the conventional technology.

Fig. 2 is the end view of the flow control valve for the construction equipment according to an embodiment of the present invention.

Fig. 3 is the end view of the main parts of the flow control valve shown in Fig. 2.

*Explanation of reference numerals for main parts in the drawing

[0015] 

1:

Hydraulic actuator

2:

Valve body

3:

Spool

4:

Pump path

5:

Supply path

6, 7:

Actuator port

10:

Tank path

11:

Check valve

12:

Pressure chamber

13, 14:

Signal pressure path

15:

Flow control valve

16, 17:

First path

18, 19:

Second path

20 :

Third path

21:

Valve spring

22:

Backward pressure chamber

23:

Drain path

DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, the flow control valve for the construction equipment according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

[0017] Fig. 2 is the end view of the flow control valve for the construction equipment according to an embodiment of the present invention, and Fig. 3 is the end view of the main parts of the flow control valve shown in Fig. 2.

[0018] With reference to Fig. 2 and Fig. 3, the flow control valve for the construction equipment according to an embodiment of the present invention is provided with a valve body (2) installed on the path between a hydraulic pump(not shown) and a hydraulic actuator (1) (e.g. boom cylinder making a boom up and down). Within the valve body (2) is provided a switchable spool (3) that by switching the same, supplies the hydraulic oil of the hydraulic pump thru an actuator port (6) on one side to the hydraulic actuator (1) and returns a hydraulic oil discharged from the hydraulic actuator (1) through an actuator port (7) on the other side to a hydraulic oil tank (not shown).

[0019] The valve body (2) is provided with a pump path (4) supplying the hydraulic oil from the hydraulic pump, a supply path (5) communicating with a pump path (4) and the actuator ports (6, 7) connected to the hydraulic actuator (1).

[0020] Within the spool (3) is provided a pressure chamber (12) that communicates with the supply path (5) and an actuator port (6) on one side.

[0021] Within the spool (3) is provided a signal pressure path (13, 14) that communicates with the actuator port (7) on the other side and the pressure chamber (12), through which the hydraulic oil returning from the hydraulic actuator (1) to the actuator port (7) on the other side is supplied as a signal pressure to the pressure chamber (12) when the pressure of the returning oil exceeds the predetermined pressure (referring to the combined force of the elastic force of a valve spring (21) plus the pressure of a back pressure chamber (22)).

[0022] The signal pressure path (13) is formed in the radial direction of the spool (3) so as to communicate with the actuator port (7) on the other side, and the signal pressure path (14) is formed in the axial direction of the spool (3) so as to communicate with the signal pressure path (13) and the pressure chamber (12).

[0023] Within the pressure chamber is provided a flow control valve (15) that is switchable and blocks the opening part by the switching activated by the returning oil through the signal pressure paths (13, 14) when the hydraulic oil returning from the hydraulic actuator (1) thru the actuator port (7) on the other side to the hydraulic oil tank exceeds the predetermined pressure

[0024] A first path (16) communicating with the supply path (5) is formed in the radial direction of the spool (3), while a first path (17) communicating with the first path (16) is formed in the axial direction at the arbitrary position of the flow control valve (15).

[0025] A second path (18) communicating with the actuator port (6) on one side is formed in the radial direction of the spool (3), while a second path (19) communicating with the second path (18) is formed in the axial direction at the arbitrary position of the flow control valve (15). The opening area of the second path (19) of the flow control valve (15) is controlled when the flow control valve (15) is switched by the hydraulic oil supplied to the hydraulic actuator (1) from the hydraulic pump as the spool (3) is switched.

[0026] A third path (20) communicating with the first path (17) and the second path (19) is formed in the axial direction of the flow control valve (15).

[0027] A drain path (23) is formed in the axial direction of the spool (3) so as to communicate with the back pressure chamber (22) and the tank path (10), and to remove the remaining pressure of the back pressure chamber (22) when the flow control valve (15) is switched.

[0028] A plug (24) is installed on an arbitrary position along the third path (20) of the flow control valve (15) so as to prevent the hydraulic oil of the hydraulic pump from flowing reversely to the actuator port on the other side as the hydraulic oil is supplied to the actuator port on one side (6 or 7).

[0029] According to the configuration as described above, the spool (3) is shifted to the left side in the figure by the pilot signal pressure in the right side of the spool (3). (At this time, the flow control valve (15) is supported by the valve spring (21) and not switched.) On the other hand, the check valve (11) is moved upwards in the figure and opened by the hydraulic oil supplied to the pump path (4) from the hydraulic pump.

[0030] Accordingly, the hydraulic oil supplied to the pump path (4) from the hydraulic pump passes through the path that is opened by the check valve(11), and delivered to the supply path (5). The hydraulic oil delivered to the supply path (5) passes through the following paths in order by the switching of the spool (3), i.e. the first path (16) communicating with the supply path (5), the first path (17) of the flow control valve (15), the third path (20), the second path (19), and the second path (18) of the spool (3), and is supplied to the actuator port on one side (6). At this moment, the hydraulic oil delivered from the supply path (5) to the actuator port on one side (6) is prevented from flowing reversely to the actuator port on other side (7) by the plug (24) installed in the third path (20) of the flow control valve (15).

[0031] At the same time, the hydraulic oil discharged from the hydraulic actuator (1) passes through the actuator (7) on the other side, the notch (9) of the spool (3), and the tank path (10) in order, and returns to the hydraulic oil tank. Thus, the hydraulic actuator (1) is actuated in contraction.

[0032] When the hydraulic oil returning from the hydraulic actuator (1) through the actuator port (7) on the other side to the hydraulic oil tank exceeds the predetermined pressure, the returning oil is provided as the signal pressure through the signal pressure paths (13, 14) communicating with the actuator port (7) on the other side.

[0033] That is, since the pressure of the returning oil exceeding the combined force of the elastic force of the valve spring (21) plus the pressure of the back pressure chamber (22) is applied in the left side of the flow control valve (15), the flow control valve (15) is switched to the right side. At this moment, the remaining pressure of the back pressure chamber (22) is discharged through the drain path (23) of the spool (3) to the tank path (10) and the valve spring (21) is put in the compression.

[0034] As mentioned above, when the flow control valve (15) is switched by the hydraulic oil returning to the hydraulic tank from the hydraulic actuator (1), the second path (19) of the flow control valve (15) is blocked from the second path (18) of the spool (3). That is, even when the first path (16) of the spool (3) is communicated with the supply path (5) by the switching of the spool (3), the path between the supply path (5) and the actuator port (6) on one side is blocked.

[0035] Accordingly, since the flow control valve (15) is switched with the opening of the same closed, the hydraulic oil can be saved, which is supplied from the hydraulic pump through the pump path (4), the supply path (5), and the actuator port (6) on one side successively to the hydraulic actuator.

[0036] On the other hand, when the hydraulic oil is not supplied anymore to the small chamber of the hydraulic actuator (1) as the hydraulic oil of the large chamber of the hydraulic actuator (1) returns to the hydraulic oil tank (the case that the pressures of the first path (16) of the spool (3), and the first path (17) and the third path (20) of the flow control valve (15) are below the predetermined pressure), the combined force of the elastic force of the valve spring (21) plus the pressure of the back pressure chamber (22) exceeds the predetermined pressure. As a result, the flow control valve (15) is switched to the left side in the figure returning to the initial position, and thus the opening of the flow control valve (15) can be kept in the maximum open state.

INDUSTRIAL APPLICABILITY

[0037] According to the present invention having the above-described configuration, the fuel efficiency can be improved as the hydraulic oil supplied from the hydraulic actuator is reduced when the pressure of the hydraulic oil returning to the hydraulic oil tank from the hydraulic actuator is higher than the predetermined pressure.

Claims

1. A flow control valve for a construction equipment comprising; a valve body (2) installed on the path between a hydraulic pump and a hydraulic actuator (1) and configured with a supply path (5) communicating with a pump path (4) supplying the hydraulic oil from the hydraulic pump and the actuator ports (6,7) connected to the hydraulic actuator (1); a spool (3) provided within the valve body (2) so that by switching, the hydraulic oil of the hydraulic pump is supplied to the hydraulic actuator (1), and a hydraulic oil discharged from the hydraulic actuator (1) is returned to a hydraulic oil tank; a pressure chamber (12) provided within the spool (3), which communicates with the supply path (5) and an actuator port (6) on one side; a signal pressure path (13, 14) provided within the spool (3), which communicates with the actuator port (7) on the other side and the pressure chamber (12) ; and a flow control valve (15) provided within the pressure chamber (12), wherein when the pressure of the hydraulic oil returning to the hydraulic oil tank from the hydraulic actuator exceeds a predetermined pressure, the flow control valve (15) is switched by the returning oil supplied through the signal pressure path (13, 14) and blocks an opening area of the flow control valve(15);
the flow control valve (15) is configured with a valve spring (21) to support elastically the maximum open state of the opening area of the flow control valve (15) as the initial state, and characterized in that
a drain path (23) is configured in the spool so as to communicate with a back pressure chamber (22) and a tank path (10) and to remove the remaining pressure of the back pressure chamber (22) by the valve spring (21).

2. The flow control valve for the construction equipment of claim 1, wherein the flow control valve (15) is configured with a first path (17) formed in the spool (3) so as to communicate with the supply path (5), a second path (18) communicating with the actuator port (6) on one side, of which the opening area is controlled when the flow control valve (15) is switched by the hydraulic oil supplied to the hydraulic actuator (1) from the hydraulic pump as the spool (3) is switched, and a third path (20) communicating with the first path (17) and the second path (18) of the flow control valve (15).

3. The flow control valve for the construction equipment of claim 2, wherein a plug (24) is installed on an arbitrary position along the third path (20) of the flow control valve (15) so as to prevent the hydraulic oil from flowing reversely to the actuator port on the other side as the hydraulic oil of the hydraulic pump is supplied to the actuator port (6 or 7) on one side.

Ansprüche

1. Flusssteuerventil für eine Bauausrüstung, umfassend: einen Ventilkörper (2), installiert auf dem Weg zwischen einer Hydraulikpumpe und einem hydraulischen Stellglied (1), und konfiguriert mit einem Zufuhrweg (5), der mit einem Pumpenweg (4) kommuniziert, der das Hydrauliköl von der Hydraulikpumpe und den mit dem hydraulischen Stellglied (1) verbundenen Stellgliedanschlüssen (6,7) zuführt; einen innerhalb des Ventilkörpers (2) vorgesehenen Schieber (3), so dass durch Schalten das Hydrauliköl der Hydraulikpumpe dem hydraulischen Stellglied (1) zugeführt wird, und ein von dem hydraulischen Stellglied (1) abgegebenes Hydrauliköl zu einem Hydrauliköltank zurückgeführt wird; eine innerhalb des Schiebers (3) vorgesehene Druckkammer (12), welche mit dem Zufuhrweg (5) und einem Stellgliedanschluss (6) auf einer Seite kommuniziert; einen innerhalb des Schiebers (3) vorgesehenen Signaldruckweg (13,14), welcher mit dem Stellgliedanschluss (7) auf der anderen Seite und der Druckkammer (12) kommuniziert; und ein Flusssteuerventil (15), vorgesehen innerhalb der Druckkammer (12), wobei dann, wenn der Druck des von dem hydraulischen Stellglied zurück in den Hydrauliköltank fließenden Hydrauliköls einen vorgegeben Druck übersteigt, das Flusssteuerventil (15) durch das zurückkehrende Öl geschaltet wird, welches durch den Signaldruckweg (13, 14) zugeführt wird, und einen Öffnungsbereich des Flusssteuerventils (15) blockiert;
wobei das Flusssteuerventil (15) mit einer Ventilfeder (21) konfiguriert ist, um den maximal geöffneten Zustand des Öffnungsbereichs des Flusssteuerventils (15) als einen initialen Zustand elastisch zu stützen, und dadurch gekennzeichnet, dass
ein Abflussweg (23) in dem Schieber konfiguriert ist, um mit einer Gegendruckkammer (22) und einem Tankweg (10) zu kommunizieren und den verbleibenden Druck der Gegendruckkammer (22) durch die Ventilfeder (21) zu entfernen.

2. Flusssteuerventil für die Bauausrüstung nach Anspruch 1, wobei das Flusssteuerventil (15) konfiguriert ist mit einem ersten Weg (17), gebildet in dem Schieber (3), um mit dem Zufuhrweg (5) zu kommunizieren, einem zweiten Weg (18), der mit dem Stellgliedanschluss (6) auf einer Seite kommuniziert, dessen Öffnungsbereich gesteuert wird, wenn das Flusssteuerventil (15) durch das von der Hydraulikpumpe dem hydraulischen Stellglied (1) zugeführte Hydrauliköl geschaltet wird, wenn der Schieber (3) geschaltet wird, und einem dritten Weg (20), der mit dem ersten Weg (17) und dem zweiten Weg (18) des Flusssteuerventils (15) kommuniziert.

3. Flusssteuerventil für die Bauausrüstung nach Anspruch 2, wobei ein Verschluss (24) an einer beliebigen Position entlang des dritten Weges (20) des Flusssteuerventils (15) installiert ist, um so das Hydrauliköl daran zu hindern, zurück zu dem Stellgliedanschluss auf der anderen Seite zu fließen, wenn das Hydrauliköl der Hydraulikpumpe dem Stellgliedanschluss (6,7) auf einer Seite zugeführt wird.

Revendications

1. Soupape de régulation de débit pour un engine de chantier comprenant : un corps de soupape (2) installé sur le trajet entre une pompe hydraulique et un actionneur hydraulique (1) et configuré avec un trajet d'alimentation (5) communiquant avec un trajet de pompe (4) fournissant l'huile hydraulique à partir de la pompe hydraulique et les orifices d'actionneur (6, 7) reliés à l'actionneur hydraulique (1) ; un tiroir cylindrique (3) prévu dans le corps de soupape (2) de sorte que, par commutation, l'huile hydraulique de la pompe hydraulique est fournie à l'actionneur hydraulique (1), et une huile hydraulique évacuée de l'actionneur hydraulique (1) soit renvoyée à un réservoir d'huile hydraulique ; une chambre de pression (12) prévue dans le tiroir cylindrique (3), qui communique avec le trajet d'alimentation (5) et un orifice d'actionneur (6) d'un côté ; un trajet de pression signal (13, 14) prévu dans le tiroir cylindrique (3), qui communique avec l'orifice d'actionneur (7) de l'autre côté et la chambre de pression (12) ; et une soupape de régulation de débit (15) prévue dans la chambre de pression (12), où lorsque la pression de l'huile hydraulique renvoyée au réservoir d'huile hydraulique à partir de l'actionneur hydraulique dépasse une pression prédéterminée, la soupape de régulation de débit (15) est commutée par l'huile renvoyée fournie à travers le trajet de pression signal (13, 14) et bloque une surface d'ouverture de la soupape de régulation de débit (15) ;
la soupape de régulation de débit (15) est configurée avec un ressort de soupape (21) pour supporter de manière élastique l'état d'ouverture maximale de la surface d'ouverture de la soupape de régulation de débit (15) en tant qu'état initial, et caractérisée en ce que
un trajet d'évacuation (23) est configuré dans le tiroir cylindrique de manière à communiquer avec une chambre de contre-pression (22) et un trajet de réservoir (10) et à supprimer la pression restante de la chambre de contre-pression (22) par le ressort de soupape (21).

2. Soupape de régulation de débit pour l'engin de chantier de la revendication 1, dans laquelle la soupape de régulation de débit (15) est configurée avec un premier trajet (17) formé dans le tiroir cylindrique (3) de manière à communiquer avec le trajet d'alimentation (5), un deuxième trajet (18) communiquant avec l'orifice d'actionneur (6) d'un côté, dont la surface d'ouverture est régulée lorsque la soupape de régulation de débit (15) est commutée par l'huile hydraulique fournie à l'actionneur hydraulique (1) à partir de la pompe hydraulique comme le tiroir cylindrique (3) est commuté, et un troisième trajet (20) communiquant avec le premier trajet (17) et le deuxième trajet (18) de la soupape de régulation de débit (15).

3. Soupape de régulation de débit pour l'engin de chantier de la revendication 2, dans laquelle un bouchon (24) est installé dans une position arbitraire le long du troisième trajet (20) de la soupape de régulation de débit (15) de manière à empêcher l'huile hydraulique de s'écouler inversement vers l'orifice d'actionneur de l'autre côté comme l'huile hydraulique de la pompe hydraulique est fournie à l'orifice d'actionneur (6 ou 7) d'un côté.

Drawing